JPS61265804A - Manufacture of electromagnetic-wave shielding material - Google Patents

Abstract

PURPOSE:To obtain an electromagnetic-wave shielding material, which can shield both an electric field and a magnetic field, by mixing amorphous alloy, which is obtained by performing plating of conducting metal and thereafter performing annealing, in paint. CONSTITUTION:Metal such as copper, tin, zinc, tin-lead alloy, silver, aluminum and nickel is plated on a hoop material of amorphous alloy. The plated hoop material is slitted into a thin thread shape. The thread shaped amorphous alloy is cut into small pieces having a the length of 0.01-5mm. The finely cut small pieces of the amorphous alloy are annealed in order to improve permeability. The small pieces are mixed in a paint, and an electromagnetic-wave shielding material is manufactured. The paint manufactured in this way is applied to cabinets for measuring instruments, medical instruments and other electronic equipment. Then electromagnetic waves from the outside are shield, and the erroneous operations of the electronic equipment and the measuring instruments can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION With the expansion of applications of electronic devices, countermeasures against electromagnetic wave interference have become necessary.

For this reason, powders such as copper, aluminum, nickel, and iron are mixed into paint to shield electronic devices and their surrounding parts from electromagnetic waves. A method of coating walls to shield electromagnetic waves has been devised and applied.

However, since copper and aluminum are metals with good electrical conductivity, they are effective in shielding electric fields, but are not effective against magnetic fields. Further, since nickel and iron are magnetic materials, they have the effect of shielding magnetic fields, but on the other hand, they are not very effective against electric fields.

Therefore, various electromagnetic wave shielding methods are currently being developed and applied, but no effective method for shielding both electric and magnetic fields has yet been developed.

Amorphous alloy is an excellent magnetic material, and its magnetic permeability in particular shows outstanding performance, with a maximum of 600,000μ, which is much higher than nickel's 400μ, and therefore has a magnetic field shielding effect. is extremely high, but on the other hand, the electric field shielding effect is small.

Therefore, if an amorphous alloy composite material in which an amorphous alloy is plated with a highly conductive material such as copper and the surface layer is covered with copper is used for shielding electromagnetic waves, the copper will shield the electric field and the amorphous will shield the magnetic field. The present inventor has experimentally discovered that it is an extremely effective electromagnetic wave shielding material that shields both electric and magnetic fields.

The method for manufacturing an effective electromagnetic shielding material using an amorphous alloy is to first prepare a hoop material of this alloy with a metal such as copper, tin, zinc, tin-lead alloy, silver, aluminum, or nickel to facilitate slitting. The plated hoop material is then slit into thin threads, the thread-like amorphous alloy is cut into pieces of 0.01 mm to 5 pieces, and the finely cut pieces of the amorphous alloy are cut into pieces to improve magnetic permeability. The pieces are annealed and mixed into paint to produce electromagnetic shielding material.

In addition, paints with a composite effect can be manufactured as electromagnetic shielding materials by mixing the amorphous alloy strips with powders of copper, aluminum, nickel, iron, silver, stainless steel, brass, etc., and mixing this into paints. Can be done.

The paint produced using this method can be applied to the housings that cover the outside of computers, measuring instruments, medical equipment, and other electronic equipment, as well as their surrounding parts, or can be applied to the entire surface of the room where the measuring instruments are installed. By coating it, it becomes an effective electromagnetic wave shielding material that blocks electromagnetic waves from outside and prevents malfunctions of electronic devices and measuring instruments.

This will be explained below using an actual flow example.

Example weight ratio: Fe 44%, Ni 44%, Mo 8%, 84%
It is an amorphous alloy with a composition of 25 μm thick and 100 μm wide.
Using an amorphous alloy hoop material with a length of 3,000 m, an electromagnetic wave shielding material for painting was manufactured through the following steps.

1) Metal plating process The above amorphous alloy hoop material was plated with copper to a thickness of 1 μm.

In this copper plating method, an amorphous alloy is plated with copper, for example, according to the plating method disclosed in Japanese Patent Application No. 60-000122 filed on January 7, 1985 by the applicant of Japan.

2) Sliding process In order to slit the amorphous hoop material coated with 1 μm copper with a width of 100 mm and a length of 3,000 m into one width, it was slit using a slitter with a cutter at intervals of one hole. ) L, 98 thread-like amorphous alloys were obtained.

(b) Cutting process The slit thread-like amorphous alloy was placed in a cutter and cut into appropriate lengths between 0.01 mm and 5 mm.

4) Annealing process The thin pieces of the amorphous alloy cut above are passed through a furnace in a nitrogen gas atmosphere set at 350°C for 5 minutes to stabilize the alloy composition and improve the magnetic permeability of the alloy. 5) Paint mixing step The pieces of the amorphous alloy obtained above were mixed into the paint in an amount of 5% to 70% by weight, and mixed in a mixer for uniformity to produce an electromagnetic shielding material for painting.

When the electromagnetic wave shielding material obtained through the above process was used to coat the entire inner wall of the room where the electronic measuring equipment was installed, there was no interference from external electromagnetic waves, and the electronic measuring equipment did not malfunction. It was recognized that the electromagnetic wave shielding effect was excellent.

Claims (1)

[Claims] A process of plating an amorphous alloy hoop material with a metal such as copper, tin, zinc, tin-lead alloy, nickel, silver, brass, or aluminum, and a process of slitting the plated hoop material. An electromagnetic shielding material comprising the following steps: cutting the slit filamentous amorphous alloy into short pieces, annealing the amorphous alloy obtained by the cutting, and mixing the annealed amorphous alloy into a paint. Production method